(IAAC) Obj: M45 (Pleiades) - Inst: Vixen 9x63 binoculars

Observation Poster: Stéphane Meloche <stephanemeloche@videotron.ca>
Observer: Stéphane Meloche
Your skills: Intermediate (some years)
Date/time of observation: 2006/01/04 6h28 UT
Location of site: Coaticook (Qc), Canada (Lat , Elev )
Site classification: Exurban
Sky darkness: 5,2 <Limiting magnitude>
Seeing:  <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: Vixen 9x63 binoculars
Object(s): M45 (Pleiades)
Category: Open cluster.
Class: C
Constellation: Tau
Data: mag 1.2  size 100'
Position: RA 03:47  DEC 24:07
I want to make an overall study of M45.  I carried out the counting of stars and determination of the colors.  Still here, the difficulty that I met is to determine which are the stars members of M45 and which are those which I will exclude.  This exercise was easier than with the Hyades, M45 is more concentrated.  After counting of stars of any brightness, I counted 55 stars.  For the study of the colouring of stars, the Pleiades have a uniformity of color much larger than their Hyades neighbors;  I did not see any member of the cluster dissociating himself with a particular color and the majority of stars are white-blue.  Only exception, the secondary star of quadruple system Alcyone (SAO 76192). This star appears more yellowish to me than the principal components of the Pleiades (those which have a proper name like Alcyone, Merope, etc).  While examining B-V indicator, all principal stars of M45, those which draw more the attention when the cluster is observed, have negative B-V, related of blue stars, from -0,02 to -0,110. The star SAO 76192, that which has a colour different from the others, has B-V of 0,024.  If there are other components of different colour that the principal members of the cluster, I did not notice them.
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